Abstract: X-ray Fluorescence Spectrometry (XRF) can be used to rapidly determine the total content of barium in barite. However, the barium carbonate included in the total barium will result in inaccurate results of barium sulfate. Moreover, copper, lead, zinc and other non-ferrous metal elements can damage the sample melting pot. Acid treatment is required to remove interference such as barium carbonate and lead. The residue ratio of the different samples after the acid treatment is different to before and the ratio of the flux to sample is uncertain, and thus the content of barium sulfate cannot be accurately determined. Therefore, it is essential to ensure that the melting agent has the same proportion as the sample. The sample pretreatment conditions, melting conditions and equipment conditions were optimized and are described in this paper. 10% hydrochloric acid mixed with 10% nitric acid was used to dissolve the sample. The sample solution was filtered to remove barium carbonate, calcium sulfate and copper, lead, zinc and other non-ferrous metal elements. Alumina oxide was added to undissolved samples after 700℃ calcination to reach the original sample weight, which attains the same proportion of flux and sample. Ammonium nitrate was used as the oxidant, and lithium bromide and ammonium iodide were used as demoulding agents. Samples were melted at 1075℃, and barium sulfate content in the barite was determined by XRF. The relative standard deviation (RSD) of the method is less than 0.4% and the detection limit is 72 μg/g. This method needs less detection time and suffers from less interference elements than determination by Inductively Coupled Plasma-Optical Emission Spectrometry, improving the test efficiency and analysis quality.